运行docker-compose up时Spring Boot应用提示无法访问application.jar如何解决？

尝试将Spring Boot项目Docker化，使用PostgreSQL作为数据库。执行docker-compose up后，数据库容器运行正常，但应用容器因「Can not access application.jar file」错误退出。本地用java -jar运行项目完全正常。

相关配置文件及日志 #

Dockerfile #

FROM openjdk:latest
RUN mkdir /app
WORKDIR /app
EXPOSE 8080
ARG JAR_FILE=./target/*.jar
COPY ${JAR_FILE} /app/application.jar
ARG HOTEL_CSV=./src/main/resources/data/hotels.csv
COPY ${HOTEL_CSV} /app/data/hotels.csv
ARG OFFERS=./src/main/resources/data/offers.csv
COPY ${OFFERS} /app/data/offers.csv

ENTRYPOINT ["java", "-jar", "application.jar"]

docker-compose.yml #

version: '3.8'
services:
  app:
    build: ./
    image: holiday-backend-app-1
    ports:
      - "8080:8080"
    volumes:
      - .:/app
      - ./data:/app/data
    depends_on:
      - db
    environment:
      SPRING_DATASOURCE_URL: jdbc:postgresql://0.0.0.0:5432/postgres
      SPRING_DATASOURCE_USERNAME: postgres
      SPRING_DATASOURCE_PASSWORD: postgres
      SPRING_DATASOURCE_DRIVER_CLASS_NAME: org.postgresql.Driver
      SPRING_JPA_SHOW_SQL: "true"
      SPRING_JPA_HIBERNATE_DDL_AUTO: create-drop
      SPRING_JPA_PROPERTIES_HIBERNATE_DIALECT: org.hibernate.dialect.PostgreSQLDialect
      server.port: 8080
      server.address: 0.0.0.0

  db:
    image: postgres
    ports:
      - "5432:5432"
    environment:
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: postgres
      POSTGRES_DB: postgres

数据库容器日志（供参考） #

The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.

The database cluster will be initialized with locale "en_US.utf8".
The default database encoding has accordingly been set to "UTF8".
The default text search configuration will be set to "english".

Data page checksums are disabled.

fixing permissions on existing directory /var/lib/postgresql/data ... ok
creating subdirectories ... ok
selecting dynamic shared memory implementation ... posix
selecting default max_connections ... 100
selecting default shared_buffers ... 128MB
selecting default time zone ... Etc/UTC
creating configuration files ... ok
running bootstrap script ... ok
performing post-bootstrap initialization ... ok
syncing data to disk ... ok


Success. You can now start the database server using:

    pg_ctl -D /var/lib/postgresql/data -l logfile start
initdb: warning: enabling "trust" authentication for local connections
initdb: hint: You can change this by editing pg_hba.conf or using the option -A, or --auth-local and --auth-host, the next time you run initdb.

waiting for server to start....2023-05-22 05:17:58.982 UTC [48] LOG:  starting PostgreSQL 15.3 (Debian 15.3-1.pgdg110+1) on aarch64-unknown-linux-gnu, compiled by gcc (Debian 10.2.1-6) 10.2.1 20210110, 64-bit
2023-05-22 05:17:58.984 UTC [48] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
2023-05-22 05:17:58.990 UTC [51] LOG:  database system was shut down at 2023-05-22 05:17:58 UTC
2023-05-22 05:17:58.997 UTC [48] LOG:  database system is ready to accept connections
 done
server started

/usr/local/bin/docker-entrypoint.sh: ignoring /docker-entrypoint-initdb.d/*

waiting for server to shut down...2023-05-22 05:17:59.103 UTC [48] LOG:  received fast shutdown request
.2023-05-22 05:17:59.105 UTC [48] LOG:  aborting any active transactions
2023-05-22 05:17:59.109 UTC [48] LOG:  background worker "logical replication launcher" (PID 54) exited with exit code 1
2023-05-22 05:17:59.112 UTC [49] LOG:  shutting down
2023-05-22 05:17:59.113 UTC [49] LOG:  checkpoint starting: shutdown immediate
2023-05-22 05:17:59.122 UTC [49] LOG:  checkpoint complete: wrote 3 buffers (0.0%); 0 WAL file(s) added, 0 removed, 0 recycled; write=0.003 s, sync=0.001 s, total=0.010 s; sync files=2, longest=0.001 s, average=0.001 s; distance=0 kB, estimate=0 kB
2023-05-22 05:17:59.130 UTC [48] LOG:  database system is shut down
 done
server stopped

PostgreSQL init process complete; ready for start up.

2023-05-22 05:17:59.234 UTC [1] LOG:  starting PostgreSQL 15.3 (Debian 15.3-1.pgdg110+1) on aarch64-unknown-linux-gnu, compiled by gcc (Debian 10.2.1-6) 10.2.1 20210110, 64-bit
2023-05-22 05:17:59.234 UTC [1] LOG:  listening on IPv4 address "0.0.0.0", port 5432
2023-05-22 05:17:59.234 UTC [1] LOG:  listening on IPv6 address "::", port 5432
2023-05-22 05:17:59.237 UTC [1] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
2023-05-22 05:17:59.242 UTC [62] LOG:  database system was shut down at 2023-05-22 05:17:59 UTC
2023-05-22 05:17:59.248 UTC [1] LOG:  database system is ready to accept connections

核心原因 #

docker-compose.yml中配置的- .:/app本地目录挂载，会覆盖容器内/app目录下的所有内容。本地项目根目录下没有application.jar（jar包存放在target目录），导致容器启动时找不到该文件。

修复步骤 #

1. 移除冲突的目录挂载 #

修改docker-compose.yml的volumes配置，删除- .:/app行。如果需要实时同步csv文件，保留对应目录挂载即可：

volumes:
  - ./src/main/resources/data:/app/data

如果不需要实时同步csv，可完全移除volumes配置（Dockerfile已将csv复制到容器内）。

2. 确保jar包已正确构建 #

先执行构建命令生成jar包：

# Maven项目
mvn clean package
# Gradle项目
./gradlew build

再重新构建镜像并启动容器：

docker-compose down
docker-compose build --no-cache
docker-compose up

3. 修正数据库连接地址 #

容器间需通过服务名通信，将数据源地址改为db（docker-compose中数据库服务的名称）：

SPRING_DATASOURCE_URL: jdbc:postgresql://db:5432/postgres

4. 可选：添加数据库就绪检查 #

depends_on仅保证容器启动顺序，不确保数据库服务就绪。可添加健康检查确保数据库就绪后再启动应用：
在db服务中添加healthcheck：

db:
  image: postgres
  ports:
    - "5432:5432"
  environment:
    POSTGRES_USER: postgres
    POSTGRES_PASSWORD: postgres
    POSTGRES_DB: postgres
  healthcheck:
    test: ["CMD-SHELL", "pg_isready -U postgres"]
    interval: 5s
    timeout: 5s
    retries: 5

在app服务中修改depends_on：

depends_on:
  db:
    condition: service_healthy

内容的提问来源于stack exchange，提问作者duckoid